Phi-3 Medium 128K vs Qwen3.5-4B
Phi-3 Medium 128K (2024) and Qwen3.5-4B (2026) are compact production models from Microsoft Research and Alibaba. Phi-3 Medium 128K ships a 128k-token context window, while Qwen3.5-4B ships a 262k-token context window. On MMLU PRO, Qwen3.5-4B leads by 27.2 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Qwen3.5-4B is safer overall; choose Phi-3 Medium 128K when provider fit matters.
Decision scorecard
Local evidence first| Signal | Phi-3 Medium 128K | Qwen3.5-4B |
|---|---|---|
| Best for | provider-routed production | multimodal apps |
| Decision fit | Coding, Long context, and Classification | Coding, Agents, and Long context |
| Context window | 128k | 262k |
| Cheapest output | $1.50/1M tokens | - |
| Provider routes | 2 tracked | 0 tracked |
| Shared benchmarks | 1 rows | MMLU PRO leader |
Decision tradeoffs
- Phi-3 Medium 128K has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Phi-3 Medium 128K for Coding, Long context, and Classification.
- Qwen3.5-4B holds a shared-benchmark lead on MMLU PRO, ahead by 27.2 points.
- Qwen3.5-4B has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Qwen3.5-4B uniquely exposes Vision and Multimodal in local model data.
- Local decision data tags Qwen3.5-4B for Coding, Agents, and Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Phi-3 Medium 128K
$775
Cheapest tracked route/tier: Microsoft Foundry
Qwen3.5-4B
Unavailable
No complete token price in local provider data
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Phi-3 Medium 128K and Qwen3.5-4B; plan for SDK, billing, or endpoint changes.
- Qwen3.5-4B adds Vision and Multimodal in local capability data.
- No overlapping tracked provider route is sourced for Qwen3.5-4B and Phi-3 Medium 128K; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Vision and Multimodal before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2024-05-21 | 2026-03-02 |
| Context window | 128k | 262k |
| Parameters | 14B | 4B |
| Architecture | decoder only | - |
| License | MIT(OSI) | Apache 2.0(OSI) |
| Openness | Open source | Open source |
| Commercial use | Commercial use allowed | Commercial use allowed |
| Knowledge cutoff | 2023-10 | - |
Pricing and availability
| Pricing attribute | Phi-3 Medium 128K | Qwen3.5-4B |
|---|---|---|
| Input price | $0.50/1M tokens | - |
| Output price | $1.50/1M tokens | - |
| Providers | - |
Capabilities
| Capability | Phi-3 Medium 128K | Qwen3.5-4B |
|---|---|---|
| Vision | No | Yes |
| Multimodal | No | Yes |
| Reasoning | No | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | No | No |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Phi-3 Medium 128K | Qwen3.5-4B |
|---|---|---|
| MMLU PRO | 51.9 | 79.1 |
Deep dive
On shared benchmark coverage, MMLU PRO has Phi-3 Medium 128K at 51.9 and Qwen3.5-4B at 79.1, with Qwen3.5-4B ahead by 27.2 points. The largest visible gap is 27.2 points on MMLU PRO, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on vision: Qwen3.5-4B and multimodal input: Qwen3.5-4B. Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
Pricing coverage is uneven: Phi-3 Medium 128K has $0.50/1M input tokens and Qwen3.5-4B has no token price sourced yet. Provider availability is 2 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Phi-3 Medium 128K when provider fit and broader provider choice are central to the workload. Choose Qwen3.5-4B when long-context analysis and larger context windows are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Phi-3 Medium 128K or Qwen3.5-4B?
Qwen3.5-4B supports 262k tokens, while Phi-3 Medium 128K supports 128k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is Phi-3 Medium 128K or Qwen3.5-4B open source?
Phi-3 Medium 128K is listed under MIT. Qwen3.5-4B is listed under Apache 2.0. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Phi-3 Medium 128K or Qwen3.5-4B?
Qwen3.5-4B has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, Phi-3 Medium 128K or Qwen3.5-4B?
Qwen3.5-4B has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Phi-3 Medium 128K and Qwen3.5-4B?
Phi-3 Medium 128K is available on Microsoft Foundry and NVIDIA NIM. Qwen3.5-4B is available on the tracked providers still being sourced. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
When should I pick Phi-3 Medium 128K over Qwen3.5-4B?
Qwen3.5-4B is safer overall; choose Phi-3 Medium 128K when provider fit matters. If your workload also depends on provider fit, start with Phi-3 Medium 128K; if it depends on long-context analysis, run the same evaluation with Qwen3.5-4B.
Continue comparing
Last reviewed: 2026-05-19. Data sourced from public model cards and provider documentation.